CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, FL, 32816, USA.
Institute of Physics NASU, Prospect Nauki, 46, Kyiv-28, 03028, Ukraine.
Chemistry. 2022 Mar 22;28(17):e202104072. doi: 10.1002/chem.202104072. Epub 2022 Mar 3.
The fast relaxation processes in the excited electronic states of functionalized aza-boron-dipyrromethene (aza-BODIPY) derivatives (1-4) were investigated in liquid media at room temperature, including the linear photophysical, photochemical, and nonlinear optical (NLO) properties. Optical gain was revealed for nonfluorescent derivatives 3 and 4 in the near infrared (NIR) spectral range under femtosecond excitation. The values of two-photon absorption (2PA) and excited-state absorption (ESA) cross-sections were obtained for 1-4 in dichloromethane using femtosecond Z-scans, and the role of bromine substituents in the molecular structures of 2 and 4 is discussed. The nature of the excited states involved in electronic transitions of these dyes was investigated using quantum-chemical TD-DFT calculations, and the obtained spectral parameters are in reasonable agreement with the experimental data. Significant 2PA (maxima cross-sections ∼2000 GM), and large ESA cross-sections ∼10 m of these new aza-BODIPY derivatives 1-4 along with their measured high photostability reveal their potential for photonic applications in general and optical limiting in particular.
室温下在液体介质中研究了功能化氮杂硼二吡咯甲川（aza-BODIPY）衍生物（1-4）的激发电子态中的快速弛豫过程，包括线性光物理、光化学和非线性光学（NLO）性质。在飞秒激发下，非荧光衍生物 3 和 4 在近红外（NIR）光谱范围内显示出光学增益。使用飞秒 Z 扫描在二氯甲烷中获得了 1-4 的双光子吸收（2PA）和激发态吸收（ESA）截面值，并讨论了溴取代基在 2 和 4 的分子结构中的作用。使用量子化学 TD-DFT 计算研究了这些染料电子跃迁中涉及的激发态的性质，并且获得的光谱参数与实验数据吻合良好。这些新的 aza-BODIPY 衍生物 1-4 具有显著的 2PA（最大截面∼2000 GM）和大的 ESA 截面∼10 m，以及它们测量的高光稳定性，揭示了它们在光子学应用中的潜力，特别是在光限域方面。
